V2x traffic maneuver handshaking between traffic participants

ABSTRACT

A vehicle broadcasts a lane change intent message indicating parameters of a maneuver to be performed by the vehicle operating as a main traffic participant vehicle, the maneuver requiring use of a road resource. Response messages are received from recipient vehicles indicating approval or disapproval of performance of the maneuver. Responsive to one of the recipient vehicles returning a response message indicating conflict with use of the road resource required for performance of the maneuver, a conflict resolution procedure is performed between the main traffic participant vehicle and the conflicted recipient vehicle, the conflict resolution procedure using a pre-agreed identical conflict resolution algorithm executed on each of the main traffic participant vehicle and the conflicted recipient vehicle to each make a same distributed decision whether to proceed with the maneuver.

TECHNICAL FIELD

Aspects of the present disclosure generally relate to handshakingbetween traffic participants over vehicle-to-everything (V2X)communication, with regard to the performance of traffic maneuvers.

BACKGROUND

V2X communication allows vehicles to exchange information with othervehicles, as well as with infrastructure, pedestrians, networks, andother devices. Vehicle-to-infrastructure (V2I) communication enablesapplications to facilitate and speed up communication or transactionsbetween vehicles and infrastructure.

SUMMARY

In one or more illustrative examples, a vehicle for performing trafficmaneuvers, includes one or more controllers. The one or more controllersare programmed to broadcast, from the vehicle to one or more recipientvehicles, a lane change intent message, the lane change intent messageindicating parameters of a maneuver to be performed by the vehicleoperating as a main traffic participant vehicle, the maneuver requiringuse of a road resource; receive, from the one or more recipientvehicles, one or more respective response messages indicating approvalor disapproval of performance of the maneuver; responsive to theresponse messages all indicating approval of the maneuver, send areservation message to at least the one or more recipient vehiclesindicating that the main traffic participant vehicle is to perform themaneuver utilizing the road resource; and responsive to one of therecipient vehicles returning a response message indicating conflict withuse of the road resource required for performance of the maneuver,perform a conflict resolution procedure between the main trafficparticipant vehicle and the conflicted recipient vehicle, the conflictresolution procedure using a pre-agreed identical conflict resolutionalgorithm executed on each of the main traffic participant vehicle andthe conflicted recipient vehicle to each make a same distributeddecision whether to proceed with the maneuver.

In one or more illustrative examples, a vehicle for vehicle forperforming traffic maneuvers includes one or more controllers. The oneor more controllers are programmed to receive, from a main trafficparticipant vehicle as a recipient vehicle, a lane change intentmessage, the lane change intent message indicating parameters of amaneuver to be performed by the main traffic participant vehicle, themaneuver requiring use of a road resource; and responsive to the roadresource being required by the recipient vehicle, perform a conflictresolution procedure between the main traffic participant vehicle andthe conflicted recipient vehicle, the conflict resolution procedureusing a pre-agreed identical conflict resolution algorithm executed oneach of the main traffic participant vehicle and the conflictedrecipient vehicle to each make a same distributed decision whether toproceed with the maneuver.

In one or more illustrative examples, a method for performing trafficmaneuvers, includes broadcasting, from a vehicle to one or morerecipient vehicles, a lane change intent message, the lane change intentmessage indicating parameters of a maneuver to be performed by thevehicle operating as a main traffic participant vehicle, the maneuverrequiring use of a road resource; receiving, from the one or morerecipient vehicles, one or more respective response messages indicatingapproval or disapproval of performance of the maneuver; responsive tothe response messages all indicating approval of the maneuver, sending areservation message to at least the one or more recipient vehiclesindicating that the main traffic participant vehicle is to perform themaneuver utilizing the road resource; and responsive to one of therecipient vehicles returning a response message indicating conflict withuse of the road resource required for performance of the maneuver,performing a conflict resolution procedure between the main trafficparticipant vehicle and the conflicted recipient vehicle, the conflictresolution procedure using a pre-agreed identical conflict resolutionalgorithm executed on each of the main traffic participant vehicle andthe conflicted recipient vehicle to each make a same distributeddecision whether to proceed with the maneuver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example system for the performance of cooperativemaneuvers including vehicles traversing a roadway;

FIG. 2 illustrates an example situation in which a vehicle intends toperform a lane change maneuver along a roadway including additionalvehicles;

FIG. 3 illustrates an example idealized message flow corresponding tothe lane change maneuver of the example situation;

FIG. 4 illustrates an example message flow corresponding to the lanechange maneuver of the example situation including a conflict and a lossof packet;

FIG. 5 illustrates an example diagram of a zero-sum conflict resolutionscenario;

FIG. 6 illustrates an example diagram of a win-win conflict resolutionscenario;

FIG. 7 illustrates an example message flow corresponding to the win-winconflict resolution scenario of FIG. 6, including a first win-winconflict resolution scheme;

FIG. 8 illustrates an alternate example message flow corresponding tothe win-win conflict resolution scenario of FIG. 6, including a secondwin-win conflict resolution scheme;

FIG. 9 illustrates an example message flow for performance of an urgentmaneuver;

FIG. 10 illustrates an example state machine for the performance ofcooperative maneuvers from the perspective of the main trafficparticipant vehicle;

FIG. 11 illustrates an example state machine for the performance ofcooperative maneuvers from the perspective of a traffic participantother than the main traffic participant vehicle;

FIG. 12 illustrates an example diagram of traffic zones that arepertinent to lane changes or other traffic maneuvers;

FIG. 13 illustrates an example diagram of a lane merge in the presenceof a vehicle behind scenario;

FIG. 14 illustrates an example diagram of a lane change in the presenceof a vehicle ahead scenario;

FIG. 15 illustrates an example diagram of a lane change in the presenceof a vehicle ahead and behind scenario;

FIG. 16 illustrates an example diagram of a negotiated gap creation inroad resource allocation scenario; and

FIG. 17 illustrates an example message flow for performance of thenegotiated gap creation.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to beunderstood, however, that the disclosed embodiments are merely examplesand other embodiments can take various and alternative forms. Thefigures are not necessarily to scale; some features could be exaggeratedor minimized to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a representative basis forteaching one skilled in the art to variously employ the embodiments. Asthose of ordinary skill in the art will understand, various featuresillustrated and described with reference to any one of the figures canbe combined with features illustrated in one or more other figures toproduce embodiments that are not explicitly illustrated or described.The combinations of features illustrated provide representativeembodiments for typical applications. Various combinations andmodifications of the features consistent with the teachings of thisdisclosure, however, could be desired for particular applications.

Through V2X communication, complex interactions between vehicles may beperformed. One illustrative example is the performance of a coordinatedcooperative lane change. An initiating traffic participant may send arequest to perform a maneuver, such as a lane change or a merge into alane (e.g., to move towards an exit, to avoid a traffic incident, avoida roadblock, lane merge, etc.). Maneuvers may be performed, forinstance, by vehicles using (i) on/off ramps, (ii) straight lanes,and/or (iii) any general adjustment of vehicle orientation. The intentof the initiating traffic participant to make the maneuver is sharedwith other traffic participants potentially involved in the maneuver.The informed traffic participants indicate agreement or disagreement ofthe planned maneuver of the initiating traffic participant. Theparticipants may then carry out the negotiated maneuvers.

To do so, a handshaking communication protocol is described. Theprotocol is robust and provides guarantee that parties either agree to amaneuver or do not maneuver if there are wireless packet losses orambiguity about intent. Moreover, techniques are described to providefor a fair allocation of road resources in this complex interaction andavoid communicating with other unnecessary vehicles. Additionally,multiple possible maneuver sharing contents are constructed, rangingfrom a maneuver path to simply a desired location within a deadline.

FIG. 1 illustrates an example system 100 for the performance ofcooperative maneuvers including vehicles 102 traversing a roadway 116.The vehicle 102 may include various types of automobile, crossoverutility vehicle (CUV), sport utility vehicle (SUV), truck, recreationalvehicle (RV), boat, plane or other mobile machine for transportingpeople or goods. In many cases, the vehicle 102 may be powered by aninternal combustion engine. As another possibility, the vehicle 102 maybe a battery electric vehicle (BEV) powered by one or more electricmotors. As a further possibility, the vehicle 102 may be a hybridelectric vehicle (HEV) powered by both an internal combustion engine andone or more electric motors, such as a series hybrid electric vehicle(SHEV), a parallel hybrid electrical vehicle (PHEV), or aparallel/series hybrid electric vehicle (PSHEV). Alternatively, thevehicle 102 may be an Automated Vehicle (AV). The level of automationmay vary between variant levels of Driver Assistance technology to afully automatic, driverless vehicle. As the type and configuration ofvehicle 102 may vary, the capabilities of the vehicle 102 maycorrespondingly vary. As some other possibilities, vehicles 102 may havedifferent capabilities with respect to passenger capacity, towingability and capacity, and storage volume. For title, inventory, andother purposes, vehicles 102 may be associated with unique identifiers,such as VINs. It should be noted that while vehicles 102 are being usedas examples of traffic participants, other types of traffic participantsmay additionally or alternately be used, such as bicycles, scooters, andpedestrians, which may be equipped with V2X technology.

The vehicle 102 may include a plurality of controllers 104 configured toperform and manage various vehicle 102 functions under the power of thevehicle battery and/or drivetrain. As depicted, the example vehiclecontrollers 104 are represented as discrete controllers 104-A through104-G. However, the vehicle controllers 104 may share physical hardware,firmware, and/or software, such that the functionality from multiplecontrollers 104 may be integrated into a single controller 104, and thatthe functionality of various such controllers 104 may be distributedacross a plurality of controllers 104.

As some non-limiting vehicle controller 104 examples: a powertraincontroller 104-A may be configured to provide control of engineoperating components (e.g., idle control components, fuel deliverycomponents, emissions control components, etc.) and for monitoringstatus of such engine operating components (e.g., status of enginecodes); a body controller 104-B may be configured to manage variouspower control functions such as exterior lighting, interior lighting,keyless entry, remote start, and point of access status verification(e.g., closure status of the hood, doors and/or trunk of the vehicle102); a radio transceiver controller 104-C may be configured tocommunicate with key fobs, mobile devices, or other local vehicle 102devices; an autonomous controller 104-D may be configured to providecommands to control the powertrain, steering, or other aspects of thevehicle 102; a climate control management controller 104-E may beconfigured to provide control of heating and cooling system components(e.g., compressor clutch, blower fan, temperature sensors, etc.); aglobal positioning system (GPS) controller 104-F may be configured toprovide vehicle location information; and a human-machine interface(HMI) controller 104-G may be configured to receive user input viavarious buttons or other controls, as well as provide vehicle statusinformation to a driver, such as fuel level information, engineoperating temperature information, and current location of the vehicle102.

The vehicle bus 106 may include various methods of communicationavailable between the vehicle controllers 104, as well as between theTCU 108 and the vehicle controllers 104. As some non-limiting examples,the vehicle bus 106 may include one or more of a vehicle controller areanetwork (CAN), an Ethernet network, and a media-oriented system transfer(MOST) network. Further aspects of the layout and number of vehiclebuses 106 are discussed in further detail below.

The TCU 108 may include network hardware configured to facilitatecommunication between the vehicle controllers 104 and with other devicesof the system 100. For example, the TCU 108 may include or otherwiseaccess a cellular modem 110 configured to facilitate communication withother vehicles 102 or with infrastructure. The TCU 108 may, accordingly,be configured to communicate over various protocols, such as with acommunication network over a network protocol (such as Uu). The TCU 108may, additionally, be configured to communicate over a broadcastpeer-to-peer protocol (such as PC5), to facilitate C-V2X communicationswith devices such as other vehicles 102. It should be noted that theseprotocols are merely examples, and different peer-to-peer and/orcellular technologies may be used.

The TCU 108 may include various types of computing apparatus in supportof performance of the functions of the TCU 108 described herein. In anexample, the TCU 108 may include one or more processors 112 configuredto execute computer instructions, and a storage 114 medium on which thecomputer-executable instructions and/or data may be maintained. Acomputer-readable storage medium (also referred to as aprocessor-readable medium or storage 114) includes any non-transitory(e.g., tangible) medium that participates in providing data (e.g.,instructions) that may be read by a computer (e.g., by theprocessor(s)). In general, the processor 112 receives instructionsand/or data, e.g., from the storage 114, etc., to a memory and executesthe instructions using the data, thereby performing one or moreprocesses, including one or more of the processes described herein.Computer-executable instructions may be compiled or interpreted fromcomputer programs created using a variety of programming languagesand/or technologies, including, without limitation, and either alone orin combination, JAVA, C, C++, C#, FORTRAN, PASCAL, VISUAL BASIC, PYTHON,JAVA SCRIPT, PERL, PL/SQL, etc.

The TCU 108 may be configured to include one or more interfaces fromwhich vehicle information may be sent and received. In an example, theTCU 108 may be configured to facilitate the collection of connectedvehicle data and/or other vehicle information from the vehiclecontrollers 104 connected to the one or more vehicle buses 106. Whileonly a single bus 106 is illustrated, it should be noted that in manyexamples, multiple vehicle buses 106 are included, with a subset of thecontrollers 104 connected to each bus 106. Accordingly, to access agiven controller 104, the TCU 108 may be configured to maintain amapping of which buses 106 are connected to which controllers 104, andto access the corresponding bus 106 for a controller 104 whencommunication with that particular controller 104 is desired.

The TCU 108 may be further configured to periodically transmit connectedmessages 120 for reception by other vehicles 102. For instance, theperiodicity may be on the order of every ten milliseconds. The TCU 108may be further configured to receive connected messages 120 from othervehicles 102. In an example, the management of sending and receiving ofconnected vehicle data may be handled by a connected application 118executed by the TCU 108. The connected messages 120 may includecollected information retrieved from the controllers 104 over thevehicle buses 106. In many examples, the collected information data mayinclude information useful for autonomous vehicle operations ordriver-assistance vehicle operations. The connected vehicle datainformation retrieved by the TCU 108 may include, as some non-limitingexamples, latitude, longitude, time, heading angle, speed, lateralacceleration, longitudinal acceleration, yaw rate, throttle position,brake status, steering angle, headlight status, wiper status, externaltemperature, turn signal status, vehicle length, vehicle width, vehiclemass, and bumper height. The connected vehicle data information may alsoinclude, weather data (such as ambient temperature, ambient airpressure, etc.), traction control status, wiper status, or other vehiclestatus information (such as the status of exterior vehicle lights, typeof vehicle, ABS system status, etc.). In one example, the connectedmessages 120 may take the form of BSM messages as described in the SAEJ2735.

While not shown, in some examples traffic participants may additionallyinvolve communication via one or more roadside units (RSUs). The RSU maybe a device with processing capabilities and networking capabilities,and may be designed to be placed in proximity of the roadway 116 for usein communicating with the vehicles 102. In an example, the RSU mayinclude hardware configured to communicate over the broadcastpeer-to-peer protocol (such as PC5), to facilitate C-V2X communicationswith the vehicles 102. The RSU may, accordingly, be able to communicatewith multiple vehicles 102 along a specific roadway 116 or in a specificarea. The RSU may also have wired or wireless backhaul capability toallow for communication with other elements of a traffic control system,via e.g., Ethernet, or cellular connection to the cellular networkinfrastructure, for example over Uu interface.

As described in further detail, the connected application 118 mayadditionally handle messaging related to the lane change handshakingbetween traffic participants using vehicle-to-everything (V2X)communication.

FIG. 2 illustrates an example situation 200 in which a vehicle intendsto perform a lane change maneuver along a roadway 116 includingadditional vehicles. As discussed herein the vehicles V1, V2 and V3 maybe vehicles 102 as discussed above with respect to FIG. 1. As shown, amain traffic participant (i.e., the vehicle V1) intends to change lanesto avoid an obstacle. The vehicle V1 may determine that V2 and V3 arerelevant to its lane change. Responsive to doing so, the vehicle V1sends a Lane Change (LC) Intent message intended for these vehicles V2,V3. It should be noted that while the illustrated lane change is betweenlanes of the roadway 116, the discussion is also applicable to a lanemerge situation, such as where the vehicle V1 intends to merge into alane from an entrance or exit ramp.

FIG. 3 illustrates an example idealized message flow 300 correspondingto the lane change maneuver of the example situation 200. This idealizedflow may sometimes be referred to as a sunny-day flow. As shown in FIG.3, and with continuing reference to FIG. 2, the main traffic participantvehicle V1 elects to perform a maneuver such as a lane change (e.g., tomove towards an exit, to avoid an incident, avoid a roadblock, lanemerge, etc.). The vehicle V1 shares this intention with other trafficparticipants potentially involved in the maneuver (here shown as V2 andV3) as a Lane Change (LC) intent message. In response, informed trafficparticipants V2 and V3 may indicate support or decline of the plannedmaneuver to the main traffic participant V1. As shown in the idealizedmessage flow 300, each of the recipient traffic participants V2 and V3responds to the LC intent message with LC Acknowledgement (ACK)messages. The main traffic participant V1 may then inform the trafficparticipants informed in the intention message (or a superset includingadditional vehicles 102 not deemed necessary for approving the maneuver)whether the vehicle 102 V1 plans to perform the maneuver. This may bedone in an LC Reservation message.

With reference to the LC intent message, the main traffic participantmay set up the LC intent message to include various information. Thisinformation may include a vehicle identifier which may be used in orderto allow other vehicles to relate the LC message to the vehicle 102 thattransmitted the message. The LC intent message may optionally includecurrent position, speed and heading of the transmitting vehicle 102.

The LC intent message may also optionally include a list of remotevehicles 102 involved in the maneuver (i.e., other vehicles 102 that aretraffic participants to the maneuver. These listed vehicles 102 may bethe vehicles 102 that should respond to the LC intent message. The listmay be deduced from the periodic connected messages 120 received fromother vehicles 102. For instance, the vehicles 102 whose locations arewithin a predefined distance to the vehicle 102 or to the intended pathfor the vehicle 102 may be indicated as being relevant participants.

The LC intent message may also include a message type. The message typemay specify the type of maneuver the main traffic participant wants toperform, e.g., lane change, driving around obstacle into a neighboringlane without a lane change, crossing a road, performing a turn at anintersection, etc. The message may also include a deadline, denotedherein by T_(TTM), which indicates a desired time by which the maintraffic participant desires to begin the maneuver (TTM indicatesTime-To-Maneuver).

The LC intent message may also include urgency information, which may bean indicator reflecting the need for the lane change or other type ofmove, e.g., to avoid an incident, to avoid a roadblock, to take anupcoming exit, etc. As one possibility, a vehicle traversing a ramp toperform a lane merge or lane exit may have a higher urgency to gainaccess to a road resource as compared to a vehicle traversing amulti-lane roadway. The LC intent message may also include a priority,which may be an indication of the priority of the vehicle intending tochange lane, e.g., a police vehicle, a school bus, an ambulance, etc.Additionally or alternatively, the LC intent message may also includeother fields such as a nonce that may be used to determine how aconflict could be resolved if more than one vehicle intends to occupythe same relative position on the road. This could include, e.g., arandomly generated number.

With respect to the intent more specifically, the LC intent message mayalso include an indication of the intended path (or multiple potentialintended paths) for main traffic participant vehicle 102. This may bespecified, as some examples, as an intended path for the next x secondsin resolution y (e.g., the trajectory for the next 10 seconds withresolution of 100 msec), in the form of a set of way points eachdetermined by their longitude/latitude, or as intended upcomingdestination by its longitude/latitude and current distance to thisupcoming intended destination. In some cases, the LC intent message mayalso include indications of intended paths or other operations to beperformed by the recipient vehicles, such as speeding up or slowing downto make a gap for the main traffic participant vehicle.

The LC intent message may also specify a road resource, denoted hereinby R, indicating the position on the road, relative to the currentposition of the main traffic participant vehicle 102, to which the maintraffic participant vehicle 102 intends to move. It should be noted thatroad resources may be relative (e.g., some portion of roadway to allowfor a lane change, although the specific portion of the roadway mayvary), or absolute (e.g., a point that must be traversed within anintersection or at a lane merge point).

Also, the LC Intent message may include a feedback type which specifiesthe type of feedback that the main traffic participant is expecting(e.g., support/reject, which variant of a maneuver is preferred,additional information, etc.). The LC Intent message may also include aManeuver ID, which is a number or other unique identifier used in themessage exchanges pertaining to this lane change maneuver requested bythe LC Intent message.

As noted above, the message exchange is initiated by the main trafficparticipant vehicle 102 sending the LC intent message to other trafficparticipants. Other vehicles 102 may then receive the LC intent message.A subset, ideally all, of these vehicles 102 are able to receive andprocess this LC intent message.

In response to the LC intent message, each participating vehicle 102 maycreate an LC response message to be returned to the main trafficparticipant vehicle 102. This LC Response message may includeinformation including the maneuver ID from the LC intent message, avehicle identifier of the responding vehicle 102, a message type (an ACKaccepting the maneuver or a NACK rejecting the maneuver indicated in theLC intent message), as well as additional information (e.g., sensorinformation that might be relevant to road resource and/or lane changeplan of the main traffic participant vehicle 102). The main trafficparticipant vehicle 102 may expect to receive the LC Response (ACK/NACK)within a predetermined interval timeout (which may be specified by theLC intent message). An ACK may be cumulative, incorporating ACKsoverheard from other vehicles 102 in the list of traffic participants.In the case of no or partial response from traffic participants, themain participant vehicle 102 may repeat the LC intent request. In manyexamples, the LC response to intent message is broadcast. However, theLC response may alternatively be sent to the main traffic participantvehicle 102 as the intended recipient.

A NACK response may be of at least two types. In one case, the NACK mayindicate a constraint pertinent to the intended maneuver, e.g., that anunequipped (or non-communicative) vehicle 102 is already occupying thespace R and is not visible to the main traffic participant. As anothercase, the NACK may indicate a conflict of interest, e.g., anothervehicle 102 is interested in the same road resource R. In this secondcase, the NACK also includes fields indicating at least deadline,urgency, and priority of the intended maneuver of the other vehicle 102.

The main traffic participant vehicle 102 may receive ACK/NACK responsesfrom surrounding traffic participants and may process them. Based onthis processing, the main traffic participant vehicle 102 makes adecision. If ACKs were received from all traffic participants, the maintraffic participant vehicle 102 sends an LC Reservation message. If oneor more ACKs were not received from all or a subset of trafficparticipants before timeout, but no NACK was received, then the maintraffic participant vehicle 102 resends the lane change intent, or sendsan LC Reservation message anyway. (The number of times the intent issent before the default action is taken may be configurable.) If atleast one NACK was received that indicated a constraint preventing themaneuver, the main traffic participant vehicle 102 aborts the maneuver.If at least one NACK was received that indicated a conflict of interest,a conflict resolution phase may be entered (discussed in detail below).

The LC reservation message may include information such as the maneuverID, a vehicle identifier of the sending vehicle 102, a message type(e.g., a road reservation signaling the decision to maneuver), and astarting time for when the main traffic participant vehicle 102 plans toinitiate the maneuver.

FIG. 4 illustrates an example message flow 400 corresponding to the lanechange maneuver of the example situation 200 including a loss of packetand a conflict resolution. With respect to the loss of packet, themessage flow 400 expands on the scenario illustrated in the idealizedmessage flow 300 by further showing that the first LC Intent message isnot responded to by the second vehicle 102 within the timeout period(which may be the result of packet loss of the LC Intent message, lossof the LC Response message, or a lack of response to a received LCIntent message). The main traffic participant vehicle 102 as shownaddresses the citation by performing a retry of the sending of the LCIntent message after expiration of the timeout.

With respect to conflict, the message flow 400 further shows apossibility in which another traffic participant vehicle 102 requestsresources. Additional messaging may then be used to perform the conflictresolution. In particular, a vehicle 102 having a conflict sends an LCResponse NACK message indicating the conflict, as explained above.Responsive to receipt of the NACK indicating the conflict, the maintraffic participant vehicle 102 may send the conflicted vehicle 102 aconflict confirmation (CC) message acknowledging and attempting toresolve the conflict. In response, the conflicted vehicle 102 may issuean LC reservation message back to the main traffic participant vehicle102 that resolves the conflict and allows the maneuver to be performed.

As some notes, the main traffic participant vehicle 102 may set atimeout to receive the LC reservation message from the conflictedvehicle 102. If the LC reservation message is not received before thetimeout expires, the conflict confirmation (CC) message may be re-sent.The conflicted vehicle V2 (i.e., not main traffic participant vehicle102) may wait for a duration of time T_(rx) to receive another conflictconfirmation, absence of which indicates receipt of reservation by V1(main participant). After verifying a full handshake (4-way), uponelapse of T_(TTM), the maneuver may be performed.

With respect to synchronization, as traffic participants need to keeptrack of the elapsed time of T_(TTM), a common time reference isrequired among the traffic participants. Continuing with reference tothe message flow 400, it is assumed that a common clock is available tothe vehicles 102 V1 and V2 (e.g., through global navigation satellitesystem (GNSS) messages). When the vehicles 102 V1 or V2 send theirrespective messages (Intent, Response ACK/NACK, CC, or Reservation), theexact timestamps at the moment of message generation are also embeddedin the messages. This ensures that (i) both vehicles 102 are aware ofthe timing of the messages and (ii) the timestamps (similar to ‘secmark’in a BSM) of intent, ACK/NACK, confirmation and reservation,respectively, are monotonically increasing in that sequence.

In case both vehicles 102 generate LC Intent messages within the sametime period (e.g., within 10 milliseconds) and the same priority andhave not yet received ACK/NACK, the vehicle 102 with the earliertimestamp may be accorded precedent.

GNSS outages or other exceptions that compromise a common clock may behandled, as a vehicle 102 may detect that the timestamp of a particularmessage is out of order. For instance, when a confirmation timestamp atvehicle 102 V1 is lower than the timestamp in the NACK from vehicle 102V2, it implies that either or both clocks on vehicles 102 V1 and V2 arenot synchronized. In such situations, vehicles 102 V1 and V2 can revertto a default action or abort the maneuver.

Regarding the loss of messages, if the vehicle 102 V1 does not receivewithin T_(rx1) (a) NACK or ACK after sending Intent, or (b) receiveReservation after sending CC, the vehicle 102 V1 may resend theserespective messages. If the vehicle 102 V2 receives a CC message withinT_(rx2) after sending a Reservation message, the vehicle 102 V2 resendsReservation message. Otherwise, the situation would mean that thevehicle 102 V1 has received the Reservation. If at any time beforemaking the maneuver, the vehicle 102 V1 elects not to proceed with theintended maneuver, the vehicle 102 V1 may optionally send out acancellation/abort message.

FIG. 5 illustrates an example diagram 500 of a zero-sum conflictresolution scenario. The zero-sum conflict resolution is one possiblemethodology for resolving a conflict between the traffic participants.In an example of such a scenario, there is a road resource R in a middlelane for which V1 and V2 compete. Because one party can win at theexpense of the other, the resolution is zero-sum.

To perform the zero-sum conflict resolution scenario, an identicalalgorithm for conflict resolution decision is implemented in eachtraffic participant vehicle 102. Thus, two vehicles 102 that have thesame input will reach an identical output (e.g., a consistent decisionwith respect to which vehicle 102 goes next). With reference to theexample message flow 400, and with continuing reference to the examplediagram 500, the Confirmation message sent by V1 may ensure that both V1and V2 have the same input to the pre-agreed identical algorithm to makethe distributed decision. The vehicle 102 that wins may send theReservation message.

The confirmation message may include information including the maneuverID, an identifier of the vehicle 102 sending the message, a Message typeindicating that this is a confirmation message that is part of conflictresolution, and a list of inputs that the traffic participants will usein performing the conflict resolution decision, e.g., priority, urgency,deadline, etc.

The reservation message may be broadcast by the vehicle 102 V2 (theresponder, not the initiating vehicle 102 with intent) and may includeat least the maneuver ID, an identifier of the vehicle 102 sending themessage, a Message type indicating that the message is a roadreservation signaling a decision as to which vehicle 102 can make themaneuver. Notably, in this scenario the responder vehicle 102 V2 sendsthe Reservation message, regardless of which of V1 and V2 has beendetermined the winner based on the decision algorithm.

An objective of the conflict resolution procedure is to prevent theoccurrence of a traffic incident. A road resource R remaining unused isundesirable, but acceptable to prevent occurrence of the incident.Validation of the incident-prevention aspects of the scheme may beconfirmed by a review of the procedure. As discussed in further detailbelow with respect to FIG. 6, responsive to V2 receiving the intentmessage from V1, V2 has information indicative of the parameters of V1and also the parameters of V2. Responsive to V1 receiving the NACKmessage from V2, V1 has information indicative of the parameters of V2and also its own parameters. Responsive to V2 receiving the CC messagefrom V1, V2 has information indicative of the parameters of V2.Responsive to V1 receiving the reservation message from V2, V1 hasinformation that V2 has received the conflict confirmation message. Atthis point, both V1 and V2 have verified that V1 and V2 have identicalinputs to the conflict resolution algorithm, resulting in identicaloutput (determining the winner). The vehicle 102 determined as winner ofthe conflict resolution can maneuver, as having been dually verified.

FIG. 6 illustrates an example diagram 600 of a win-win conflictresolution scenario. The win-win conflict resolution is another possiblemethodology for resolving a conflict between the traffic participants.As opposed to the zero-sum conflict resolution that decides access to aresource R, the win-win conflict resolution chooses among multiple setsof pathways.

The win-win conflict resolution procedures may make use of thecake-cutting algorithm, which is a fair-allocation game that identifiestwo different roles: a cake cutter party, and a cut selector party. Theformer and the latter parties are mutually exclusive. The cake cutterparty cuts a given cake into two pieces. If the cake cutter makes unfaircuts, the cut selector can select the bigger piece. Thus, the cakecutter is incentivized to make a fair cut. This algorithm is customizedand modified for vehicle maneuver use cases. In the present case, thecake cutting problem is modified to a set (that may include multiplepossibilities). The cake cutter party devises the possible pathways, andthe cut selector selects one pathway. The complementing subset to thepathway selected is allotted to the cake cutter party. In the win-winmethod for conflict resolution, the conflict confirmation signalincludes the proposed set of pathways. A follow up message is sent by V2that determines the selected pathway V1 needs to send an ACK to thismessage and confirm selection.

Similar to the zero-sum conflict resolution procedure, the generalmessage sequence may be performed such that (i) the vehicle 102 V1 sendsan LC Intent message, (ii) a recipient vehicle 102 such as V2 sends aNACK indicating contention, and (iii) the vehicle 102 V1 sends aconflict confirmation (CC) message. However, to allow for the choicebetween the multiple sets of pathways, the Intent, ACK, and CC messagescontain additional information.

FIG. 7 illustrates an example message flow 700 corresponding to thewin-win conflict resolution scenario of the example 600, including afirst win-win conflict resolution scheme. As shown, the vehicle 102 V1sends an LC Intent message with fields similar to those previouslydescribed for the zero-sum conflict resolution procedure. In response toreceipt of the LC Intent message, the vehicle 102 V2 sends a NACKmessage with fields similar to those previously described in zero-sumconflict resolution, but with the addition of a set of possible pathwaysP. In this first scheme, the vehicle 102 V2 is the cake cutter player inthe cake-cutting algorithm (i.e., the vehicle V2 makes the cut, and thevehicle V1 chooses). Responding to the existence of a conflict betweenthe intent of the vehicle 102 V1 and the operation of the vehicle 102V2, the vehicle 102 V2 creates the set P including three proposedpathways: {A, 0B, 00C} (in the example, each letter denoting analternate path, the “0” terminology denoting continuing motion in thecurrent lane for the next L meters.). The vehicle 102 V2 returns thismessage including the set P back to the vehicle 102 V1. Having the setP, the vehicle 102 V1 chooses one of the possibilities, and sends aconflict confirmation message including one of the specific pathways sϵP(e.g., A). Accordingly, the vehicle 102 V1 fulfills its role as cutselector in the cake-cutting algorithm. The vehicle 102 V2 receives theconflict confirmation messages, and in response, sends a reservationmessage that acknowledges the selected pathway of the vehicle 102 V1 andincludes the selected pathway q of the vehicle 102 V2 selected from set{∀x∈P,x≠s}, e.g., 0B. With the conflict resolved, the vehicles 102 V1and V2 may proceed.

FIG. 8 illustrates an alternate example message flow 800 correspondingto the win-win conflict resolution scenario of the example 600,including a second win-win conflict resolution scheme. As shown, thevehicle 102 V1 sends an LC intent with fields similar to thosepreviously described in case A, plus a set of possible pathways Panticipating and provisioning a conflict of interest. As opposed to thescenario shown in the message flow 700, here, V1 is the cake cutter, notV2. Here, the vehicle 102 V1 creates the set P including three proposedpathways: again using the example of {A, 0B, 00C}. In response toreceipt of the LC Intent message, the vehicle 102 V2 sends a NACKmessage with fields similar to those previously described in thezero-sum case, plus a specific pathway sϵP, e.g., A. Thus, here thevehicle 102 V2 is a cut selector in the cake-cutting algorithm.Responsive to receipt of the NACK message, the vehicle 102 V1 sends aconflict confirmation message that acknowledges the selected pathwayfrom V2 and includes the selected pathway q selected by V1 from set{∀x∈P,x≠s}, e.g., 0B. Next, the vehicle 102 V2 sends a reservationmessage that includes the selected pathway q made by V2. With theconflict resolved, the vehicles 102 V1 and V2 may proceed.

It should be noted that if vehicle 102 V1 and vehicle 102 V2 almostsimultaneously send an LC Intent message, the LC Intent message with theolder timestamp may take priority. For example, if the timestamp of theLC Intent message sent by V1 is older, upon receiving the LC Intentmessage from the vehicle V1, the vehicle V2 sends a NACK to the LCIntent message from V1, but V2 does not resend its LC Intent messageagain.

Referring collectively to the first and second win-win conflictresolution schemes, the first scheme has the advantage that it allows ashorter LC Intent message, and does not require the vehicle 102 that issending the initial LC Intent message to proactively consider possiblepathways in case there would be a conflict of interest. However,regarding the second scheme, it has better coordinating featurescompared to the first scheme, as each of the pathway selected by oneparty are acknowledged by the other party. It should also be noted thatin yet another example, V1 may send the list of options to V2 in the LCintent message, despite not being aware of the intended road resource ofV2.

FIG. 9 illustrates an example message flow 900 for performance of anurgent maneuver. In this case, the main traffic participant vehicle 102attempts to perform a lane change to prevent an incident occurring withanother vehicle 102 or with a roadblock or other object. As shown, themessage exchange is shortened, skipping multiple messages due to theurgency of the situation. The initial LC Intent message sent by the maintraffic participant vehicle 102 indicates both intent and reservation.The remaining content of the LC Intent message is substantially similarto or the same as those listed in the other message flows. The LC Intentmessage may be sent multiple times and reinforced with HARQ to ensureits delivery and receipt by other traffic participants.

With respect to aborting maneuvers, such as the sunny-day scenario, theconflict resolution scenarios, or the urgent maneuver scenario, trafficparticipants may have a default (abort) maneuver option. In the zero-sumexamples, a winner traffic participant may change intent and decideagainst performing the maneuver. To do so, the winner sends an abortmessage anytime to signal that vehicle 102 is going to perform a defaultaction instead. In the win-win examples, any vehicle 102 may send theabort message to signal that the respective traffic participant is goingto perform the default action. Other vehicles may elect to proceed asagreed. In the case of a negotiation not agreed until T_(TTM) haselapsed, both (or all) traffic participants may execute their respectivedefault actions. By default action, it is meant that both (or all)vehicles are on their own and take actions (such as keeping in theircurrent lanes etc.).

With respect to post-conditions, in case of a decision to perform thelane change, the main traffic participant vehicle 102 initiates themaneuver at the time indicated in the reservation. Other vehicles 102may take appropriate actions (possibly before the initiation timeinstant of the main traffic participant). In case of a decision not toperform the maneuver, traffic flows as before, without performing themaneuver. It should be noted that the traffic participants might decideto attempt similar or alternative maneuvers instead.

The methodology described herein may be useful in a variety of maneuversituations. For instance, for a cooperative lane change, the maintraffic participant may be a host vehicle 102. The host vehicle 102 mayintend to perform a lane change, but there may be remote vehicles 102 onthe lane adjacent to the lane the host vehicle 102 wants to change to.To prevent two vehicles 102 simultaneously attempting to change lane,the host vehicle 102 sends a LC Intent message. The remote vehicle 102receives it and after processing the message responds with an ACKindicating that the host vehicle 102 can proceed. Upon receiving theACK, the host vehicle broadcasts a reservation message, and subsequentlyproceeds with the lane change.

In a high-priority lane change, the main traffic participant is a hostvehicle 102. There is a vehicle 102 on course towards the host vehicle102. The host vehicle 102 intends to perform a lane change to avoid thesituation, but there are remote vehicles 102 on the lane adjacent to thelane the host vehicle 102 wants to change to. To prevent two vehicles102 simultaneously attempting to change lane, the host vehicle 102 sendsa lane change intent and reservation message. The remote vehicle 102receives it and after processing the message response does not make alane change. The host vehicle 102 proceeds with lane change.

In a road blockage scenario, one lane of a rural road is blocked by anobstacle or other traffic. The blocked vehicle 102 intends to changelanes and avoid coming to a full stop. The host vehicle 102 approachingthe obstacle may send an LC Intent message indicating it desires tochange lanes. Another vehicle 102 in the lane adjacent to the lane thehost vehicle 102 intends to move to, also wants to change lane,resulting in a conflict. The host vehicle 102 sends an LC intent messagewhich is responded to by the remote vehicle 102 by a NACK indicatingconflict. The host vehicle 102 sends a subsequent conflict message thatconveys the urgency, priority and other relevant parameters to themaneuver. Each of the host and remote vehicles 102 individually uses thesame input and algorithm and determines that the host vehicle should gofirst. The host vehicle 102 sends a reservation message and thenproceeds with lane change.

An exception event may also occur, which is analogous to an interruptionwhile vehicles 102 are engaged in a cooperative lane maneuver.Exceptions may be driven by a variety of factors such as, but notlimited to (i) traction control loss of one or more participatingvehicles 102, (ii) an entering (non-cooperative) vehicle 102 approachingin the road section that is being negotiated, (iii) hard braking orevasive action that participating vehicles 102 have to perform due tosudden appearance of an obstruction. Exception events may abort anyon-going cooperative lane change agreements between participatingvehicles 102, which will instead default to taking independent decisionson their respective maneuvers. Participating vehicles 102 may then alsotransmit abort messages to inform neighboring vehicles 102 of this.

FIG. 10 illustrates an example state machine 1000 for the performance ofcooperative maneuvers from the perspective of the main trafficparticipant vehicle 102. As shown, the diagram illustrates the states ofthe vehicle 102 as well as the criteria for transition between thestates.

In the IdleState, responsive to receiving a command to initiate amaneuver, the vehicle 102 may, if traffic rules or some other reasonprevent performance of a maneuver, remain in the IdleState. In doing so,the vehicle 102 may one or more of check current rules and constraints,assess the state of the road and traffic, and inform the driver or thevirtual driver system that the maneuver cannot proceed. If nothingprevents the maneuver from proceeding, the vehicle 102 may enter theSendIntent state. In doing so, the vehicle 102 may one or more of checkcurrent rules and constraints, assess the state of the road and traffic,transition to the SendIntent state, start an ACK_NACK_TO timeout, andstart a TTM_Timer.

In the SendIntent state, responsive to receiving an ACK message, if onlysome but not all ACK messages from the vehicles 102 on the ACK list arereceived, the vehicle 102 may wait and remain in the SendIntent state.If all ACKs have been received, the vehicle 102 may one or more ofcancel the ACK_NACK_TO, and transition to the SentReservation state (orpossibly keep sending the Reservation until the TTM_timer expires). If,however, the ACK_NACK_TO timeout expires without all of the ACK or NACKfrom the list being received, the vehicle 102 may one or more oftransition to SendIntent, and reset the ACK_NACK_TO timeout.

In the SendReservation state, responsive to expiration of the TTM_Timer,the vehicle 102 transitions to ManeuverActivated. Or, if while in theSendReservation state an abort message is received or the vehicle 102itself aborts, the vehicle 102 performs one or more of to cancel theTTM_timer, set the AbortTimer, and transition to the AbortState.

In the ManeuverActivated state, responsive to the maneuver beingcompleted, the vehicle 102 does one or more of perform the maneuver,record the performed actions and transition back to the IdleState.

In the AbortState, responsive to receipt of a message from one of thetraffic participants, the vehicle 102 may perform one or more of toresend the abort message, reset the AbortTimer, but may remain in theAbortState. Responsive to expiration of the AbortTimer, the vehicle 102may transition to the IdleState.

Turning to conflict resolution, if, while in the SendIntent state, aNACK is received indicating physical restriction to maneuver (other thanconflict), the vehicle 102 may one or more of cancel the TTM_timer,cancel the ACK_NACK_TO timer, and transition to the AbortState. If oneNACK message is received indicating conflict, and all ACK/NACK responseshave been received, the vehicle 102 may perform one or more of to statethe CC_Timer, and transition to the SentCC state. If more than one NACKmessage is received indicating conflict, the vehicle 102 may perform oneor more of to cancel the TTM_Timer, cancel the ACK_NACK_TO timer, andtransition to the AbortState. Also, if the TTM_Timer expires, or thevehicle 102 changes intent, the vehicle may also transition to theAbortState.

In the SentCC state, responsive to the vehicle 102 receiving areservation message indicating that negotiation is completed and inwhich the vehicle 102 is allocated a road resource/pathway, the vehicle102 performs one or more of to compute conflict resolution using itsalgorithm common to the traffic participants, wait for the TTM timer toexpire, and transition to the ManeuverActivated state. Responsive to thereservation message indicating that negotiation is completed and thevehicle 102 is not allocated a road resource/pathway, the vehicle 102performs one or more of to compute conflict resolution using itsalgorithm common to the traffic participants, delete the CC_Timer,delete the TTM timer, perform the default action and not the maneuver,and transition to the IdleState. If the TTM timer expires withoutreceipt of the reservation message, the vehicle 102 may one or more ofreset the CC_Timer, and remain in the SentCC state. If the TTM Timerexpires without receipt of the reservation message, the vehicle 102 maytransition to the AbortState.

Regardless of state, if a high-priority maneuver event is received, thevehicle 102 may be required to act regardless of negotiation. In such aninstance, the vehicle 102 may one or more of abort the current action,cancel any timers, activate a high-priority action timer, and transitionto the SentIntentReservation state. In the SentIntentReservation state,responsive to expiration of the high-priority action timer, the vehicle102 transitions to the ManeuverActivated state to perform the maneuver.

FIG. 11 illustrates an example state machine 1100 for the performance ofcooperative maneuvers from the perspective of a traffic participantother than the main traffic participant vehicle 102. As shown, thediagram illustrates the states of the vehicle 102 as well as thecriteria for transition between the states.

In the IdleState, responsive to the vehicle 102 receiving an intent tomaneuver from the main traffic participant vehicle 102, and the vehicle102 has no intent to change lane; and the vehicle 102 sees no physicalconstraint on the maneuver proposed by the main traffic participantvehicle 102, the vehicle 102 may one or more of start the TTM Timer,send an ACK message, and transition to the SendACK state.

In the SendAck state, responsive to the vehicle 102 not receiving thereservation message before expiration of the TTM Timer, the vehicle 102deletes the TTM Timer and transitions back to the IdleState. Or,responsive to the vehicle 102 receiving another intent message,indicating that a previous ACK message was lost, the vehicle 102 resendsthe ACK message and remains in the SendAck state. Responsive to receiptof the reservation message, the vehicle 102 may wait for the TTM Timerto elapse and then returns to the IdleState.

Also in the IdleState, responsive to the vehicle 102 receiving an intentto maneuver from the main traffic participant vehicle 102, and thevehicle 102 indicating a physical restriction to movement of the vehicle102 (other than a conflict), the vehicle 102 sends a NACK messageindicating the physical restriction and transitions to the SendNACKstate. Also responsive to the vehicle 102 receiving an intent tomaneuver from the main traffic participant vehicle 102, and the vehicle102 indicating a physical restriction to movement of the vehicle 102(other than a conflict), the vehicle 102 sends a NACK message indicatingthe conflict and transitions to the SendNACK state.

In the SendNACK state, responsive to the vehicle 102 receiving anotherintent message indicating that the previous NACK was lost, the vehicle102 may resend the NACK message, e.g., indicating the physicalrestriction or conflict as noted above. Responsive to receipt from themain traffic participant vehicle 102 of an abort message, the vehicle102 may cancel all timers and return to the IdleState. Responsive toexpiration of the TTM Timer, the vehicle 102 may also delete the timersand return to the IdleState.

If, however, in the SendNACK state, the vehicle 102 having send a NACKmessage indicating a conflict and then having received a conflictconfirmation message, the vehicle 102 enters conflict resolution. Indoing so, the vehicle 102 may one or more of compute the conflictresolution using its algorithm shared among the vehicles 102, send areservation message, start the CC timer, and transition to theSentReservation state.

In the SentReservation state, responsive to receipt of another conflictconfirmation message, the vehicle 102 may infer that the reservationmessage was lost, and may resend the reservation message, reset the CCtimer, and remain in the SentReservation state. Responsive to timeout ofthe CC timer, negotiation for the conflict being completed, and thevehicle 102 not receiving a road resource or pathway, the vehicle 102one or more of waits for the TTM timer to expire, deletes the timers,and returns to the IdleState. Responsive to timeout of the CC timer,negotiation for the conflict being completed, and the vehicle 102receiving a road resource or pathway, the vehicle 102 waits for the TTMtimer to expire. Responsive to expiration of the TTM timer, the vehicle102 having received the road resource or pathway, the vehicle 102transitions to ManeuverActivated to perform the maneuver.

In the ManeuverActivated state, responsive to the maneuver beingcompleted, the vehicle 102 does one or more of perform the maneuver,record the performed actions and transition back to the IdleState.

Regardless of state, if a high-priority maneuver event is received, thevehicle 102 may be required to act regardless of negotiation. In such aninstance, the vehicle 102 may one or more of abort the current action,cancel any timers, activate a high-priority action timer, and transitionto the SentIntentReservation state. In the SentIntentReservation state,responsive to expiration of the high-priority action timer, the vehicle102 transitions to the ManeuverActivated state to perform the maneuver.

Also regardless of state, if an exception occurs requiring the vehicle102 to opt-out, the vehicle 102 sends an abort message and transitionsto the AbortState. In the AbortState, the vehicle 102 may awaitexpiration of the AbortTimer and transition to the IdleState.

FIG. 12 illustrates an example diagram 1200 of traffic zones that arepertinent to lane changes or other traffic maneuvers. These include afast approach zone (FAZ) as well as a proximity zone (PZ). The FAZ mayrefer to an area in the adjacent lane from 30 to 162 ft (˜9 m-50 m)behind the rear bumper of the vehicle 102, while the PZ may refer to anarea in the adjacent lane from 4 ft (1.2 m) in front of the front bumperof the vehicle to 30 ft (9 m) behind the rear bumper of the vehicle 102.The PZ area generally includes the blind spot and the area beside andbehind the vehicle 102. The most common lane-change incidents appear tobe those occurring in the PZ. Both the PZ and the FAZ refer to areasthat should be monitored before lane-change initiation.

Another determining factor in defining the negotiation zone is the timeit takes to complete negotiation and the actual maneuver. Over manyexamples, lane-change duration has been studied to be between 1.0 secondto 13 seconds, with a mean of 4.6 seconds. Note that this is contrary tothe assumed fixed duration of 1.5 seconds typically assumed for theactual maneuver. Considering these values, denoting the maneuver time byT_(M), and the preceding negotiation period by T_(N), the total time forplanning and executing a lane change is T_(M)+T_(N). During this period,it is envisioned that a vehicle 102 would have access to a fixedsnapshot of the road dynamics, i.e., no unforeseen vehicles 102 enteringthe scene and preventing lane change, no sudden accelerations orslowdowns of the neighboring vehicles 102, etc.

Assume, for sake of example, a 5 seconds lane change duration, and a 1.5second negotiation period that precedes the maneuver. Note that 1.5seconds of negotiation is approximated by a 4-way handshake (2 RoundTrip Times (RTT)), and assuming each RTT to be 300 msecs (which is alarge RTT and incorporates high queuing and processing delay). Thisresults in 600 msec negotiation time. Accounting for retransmission oflost packets and considering margins, 1.5 seconds should be sufficientlylarge to accommodate all signaling preceding any maneuver.

This sums to a 6.5 seconds period, during which ideally no changes occurin the surrounding dynamics, i.e., no unforeseen traffic participant toenter the negotiation zone. Thus, a vehicle 102 that is more than 6.5seconds distant from the main traffic participant vehicle 102 can beexcluded from the negotiation, i.e., is out of the negotiation zone.Note that the above calculation does not consider the case of heavyvehicles 102 whose lane change takes longer. For light-weight vehicles102 in highway scenarios at speed of 80 mph (130 km/h=36 m/sec), 6.5seconds of headway amounts to 234 meters. At urban scenarios with speedof 40 mph, this headway would be less than 120 meters.

Based on the above two constraints, the negotiation zone should bedefined to include at least the PZ. It is reasonably required for it toalso include FAZ. Furthermore, depending on the type of the vehicle 102changing lane (e.g., heavy load vehicle 102 versus lighter passengervehicles 102) and the duration of lane change, another zone boundary maybe determined based on the amount of notification time required ahead oflane change.

FIG. 13 illustrates an example diagram 1300 of a lane merge in thepresence of a vehicle 102 behind scenario. As shown, the vehicle 102 V1intends to change lanes to the middle lane, and negotiates this movewith vehicle 102 V2 ahead of time. However vehicle 102 V3 that waspreviously outside the negotiation zone is approaching R rapidly, movingat a speed faster than V1. For V3 to maintain a distance with V1 afterits lane change to the middle lane, V3 should have a headway of about 2seconds to V1.

A vehicle may use the dimensions of PZ and FAZ with available kinematicsfrom BSMs of other vehicles to estimate overlap with their futurelocations. Once a zone is defined based on the considerations discussedabove, the newly occupied road resource R should have sufficientdistance to V3. If one of the following conditions holds, Vx (thevehicle—either V1 or V2—winning R and changing lane) may either (a)abort lane change, (b) speed up after changing lane, (c) speed up beforechanging lane, or (d) request V3 to decrease its speed before Vx's lanechange or (e) request V3 to decrease its speed after Vx's lane change.These methods (a) through (e) are discussed in further detail withrespect to the following examples.

Upon lane change, the PZ of Vx may overlap with the PZ of V3. In thiscase, R should not be considered a viable road resource for lane change.As V3 is in the negotiation zone of V1 and V2, V3 is part of thenegotiation protocol, after receiving intent, the maneuver is notpossible in the given conditions. Thus, one of the methods enumeratedabove (a) through (e) may be used (if feasible): e.g., using (a), V3should respond with a NACK (of constraint type) and the maneuver beaborted, or using (d), if V3 is not already moving at the minimumallowed speed, V3 may send an ACK and decelerate to create a gap betweenitself and R that keeps R out of PZ.

In may be that the FAZ of Vx overlaps with the PZ of V3. If stayingclear of both PZ and FAZ is required, like the previous case, this isnot allowed. If partial FAZ overlap is allowed, depending on what isconsidered a suitable distance between two vehicles 102 (e.g., 2 secondheadway, or allowing a specific partial overlap with FAZ), this case maybe allowed. If the distance between R and V3 is smaller than thesuitable distance allowed, one of the methods (a) through (e) may betaken. For example:

If d(V3, R)<d_(min), one of the following may be decided. Based on (a),R should not be considered a valid road resource for lane change. As V3is in the negotiation zone of V1 and V2, V3 is part of the negotiationprotocol, after receiving intent, V3 should respond with a NACK (ofconstraint type). Based on the method (b) mentioned above, Vx needs tospeed up after lane change to reach d_(min) between itself and V3, whered_(min) is the minimum allowed distance between two vehicles. Based onthe method (d) mentioned above, if possible, (V3 not already going atminimum allowed speed), V3 may send an ACK and decelerate to create agap between itself and R that keeps required inter-distance d_(min).

If the velocity of V3 is greater than that of Vx (the vehicle winning Rand changing lane), one of the previously named options may be taken.For example, using the method (b) mentioned above, Vx speeds up afterlane change if possible/feasible.

Using the method (d) mentioned above, if possible, (V3 not already goingat maximum allowed speed), V3 may send an ACK and decelerate to create agap between itself and R that keeps required inter-distance d_min.

FIG. 14 illustrates an example diagram 1400 of a lane change in thepresence of a vehicle 102 ahead scenario. As shown, in the scenariothere is a vehicle V3 ahead of V1 and V2. For a lane change by one of V1and V2 to change lanes, the newly-occupied road resource R should havesufficient distance to V3.

If one of the following conditions holds, Vx (the vehicle—either V1 orV2—winning R and changing lane) may either (a) abort lane change, (b)slow down after changing lane, (c) slow down before changing lane, (d)request V3 to increase its speed before Vx's lane change, or (e) requestV3 to increase its speed after Vx's lane change.

In the situation where the PZ of V3 overlaps with R, R should not beconsidered a viable road resource for lane change. As V3 is in thenegotiation zone of V1 and V2, V3 is part of the negotiation protocol.After receiving the LC Intent message, the maneuver is not possible inthe given conditions. Thus, one of the 5 methods enumerated above (a)through (e) may be used (if feasible): e.g., using (a), V3 shouldrespond with a NACK (of constraint type) and the maneuver be aborted, orusing (d), if V3 not already moving at the maximum allowed speed, V3 maysend an ACK and accelerate to create a gap between itself and R thatkeeps R out of PZ.

In the situation where the FAZ of V3 overlaps with R, if staying clearof both PZ and FAZ is desired, as in the previous case, the maneuver isnot allowed. If a partial FAZ overlap is allowed, depending on what isconsidered an adequate distance between two vehicles 102 (e.g., 2 secondheadway, or allowing a specific partial overlap with FAZ), this case maybe allowed. If the distance between R and V3 is smaller than thesuitable distance allowed, one of the methods (a) through (e) may betaken. For example If d(V3, R)<d_(min), one of the following may bedecided. Based on (a), R should not be considered a valid road resourcefor lane change. As V3 is in the negotiation zone of V1 and V2, V3 ispart of the negotiation protocol, after receiving intent, V3 shouldrespond with a NACK (of constraint type). Based on the method (b)mentioned above, if feasible Vx slows down after the lane change toreach d_(min) between itself and V3, where d_(min) is the minimumallowed distance between two vehicles. Based on the method (d), ifpossible, (V3 not already going at maximum allowed speed), V3 may sendan ACK and accelerate to create a gap between itself and R that keepsrequired inter-distance d_(min).

In the case where the velocity of V3 is smaller than that of Vx (thevehicle winning R and changing lane), one of the previously namedoptions may be taken. For example, using (b), Vx needs to slow downafter lane change. Or, using (d), if possible, (V3 not already going atmaximum allowed speed), V3 may send an ACK and accelerate to create agap between itself and R that keeps required inter-distance d_(min).

The minimum distance d_(min) may be defined as PZ, or PZ+FAZ, or PZ andpart of FAZ. The negotiation zone may be selected symmetrically forvehicles 102 ahead and vehicles 102 behind the main traffic participantvehicle 102 V1. For example, as shown in the diagram 1400, with regardto a lane merge in presence of a vehicle 102 behind wherein a vehiclemore than 6.5 seconds away and behind main participant is out of thenegotiation zone, the same margin of 6.5 seconds may be enforced forvehicles 102 ahead. It should also be noted that d_(min) may be selectedsuch that it does not impose a tighter constraint than the negotiationzone. If d_(min) extends beyond the negotiation zone, V3 is excludedfrom negotiation zone, and thus would not send an ACK or NACK, or takeany action to accommodate the lane change for Vx.

FIG. 15 illustrates an example diagram 1500 of a lane change in thepresence of a vehicle ahead and behind scenario. In the general case,there are typically vehicles 102 both ahead and behind the main trafficparticipant vehicle 102 (in this example the vehicle 102 V1). In thiscase, both vehicles V3 and V4 may be part of the negotiation. If theroad resource R overlaps with the zones considered for one of V3 and V4,as a result of negotiation, a gap may be created by V3 and V4 to allowsufficient space for V1 or V2 to perform a lane change maneuver. Forexample, V4 may agree to slow down to accommodate a merge, and/or V3 mayagree to speed up. The options available for the traffic participants inthis case are the feasible set of combinations of options (a) to (e) forthe vehicle ahead, and their parallels for the vehicle 102 behind.

FIG. 16 illustrates an example diagram 1600 of a negotiated gap creationin road resource allocation scenario. As shown, another approach tomaking maneuvers is to negotiate for sufficiently wide gaps betweenvehicles 102. Considerations for adaptive cruise control presume a timegap margin. A time gap margin is the current speed of the vehicle 102times a nominal reaction and deceleration time (e.g., at 70 MPH with 1.2sec gap is about 37 m). Such vehicles 102 may also change their lanes.At higher speeds, the time gap distance thus becomes larger. A use casemay activate when the vehicle 102 is above a certain speed. If either V2or V3 sends a NACK, the exception requires an abort message. At most,two vehicles 102 may define bounds of the conflict region. Otherwise,considering more than two the complexity of the road resource allocationproblem scales rapidly. Thus each cooperating vehicle 102 may ask fortwo more vehicles 102 to make an appropriate gap. In some examples, onlyone cooperating vehicle 102 may be utilized to initiate a gap creationmaneuver. V2 and V3 may not only use speed adjustment, but they may alsochange lanes to assist in gap creation.

FIG. 17 illustrates an example message flow 1700 for performance of thenegotiated gap creation. In one possible approach, vehicles 102 V2 andV3 send a maneuver completion message to let V1 begin moving in the gap(it is not relevant to V2 and V3 what V1 does in the meantime). Inanother possible approach, BSMs or other connected messages 120 may beused to facilitate judgment for maneuvering. For instance, V1 may starta maneuver whenever it detects that a sufficient gap has opened up.

Variations on the described examples are possible. In one example, a RSUmay perform one or more of the roles described herein as being performedby the vehicles 102. For instance, the handshaking may adapt such thatresponsive to a main traffic participant vehicle 102 V1 sending arequest, the RSU assigns the request and designates a road resource. Asanother possibility, if multiple vehicles send a request for a roadresource within a short timeframe, the RSU may assign non-overlappingroad resources to the multiple vehicles.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms encompassed by the claims.The words used in the specification are words of description rather thanlimitation, and it is understood that various changes can be madewithout departing from the spirit and scope of the disclosure. Aspreviously described, the features of various embodiments can becombined to form further embodiments of the invention that may not beexplicitly described or illustrated. While various embodiments couldhave been described as providing advantages or being preferred overother embodiments or prior art implementations with respect to one ormore desired characteristics, those of ordinary skill in the artrecognize that one or more features or characteristics can becompromised to achieve desired overall system attributes, which dependon the specific application and implementation. These attributes caninclude, but are not limited to cost, strength, durability, life cyclecost, marketability, appearance, packaging, size, serviceability,weight, manufacturability, ease of assembly, etc. As such, to the extentany embodiments are described as less desirable than other embodimentsor prior art implementations with respect to one or morecharacteristics, these embodiments are not outside the scope of thedisclosure and can be desirable for particular applications.

What is claimed is:
 1. A vehicle for performing traffic maneuvers,comprising: one or more controllers programmed to broadcast, from thevehicle to one or more recipient vehicles, a lane change intent message,the lane change intent message indicating parameters of a maneuver to beperformed by the vehicle operating as a main traffic participantvehicle, the maneuver requiring use of a road resource; receive, fromthe one or more recipient vehicles, one or more respective responsemessages indicating approval or disapproval of performance of themaneuver; responsive to the response messages all indicating approval ofthe maneuver, send a reservation message to the one or more recipientvehicles indicating that the main traffic participant vehicle is toperform the maneuver utilizing the road resource; and responsive to oneof the recipient vehicles returning a response message indicatingconflict with use of the road resource, perform a conflict resolutionprocedure between the main traffic participant vehicle and theconflicted recipient vehicle, the conflict resolution procedure using apre-agreed identical conflict resolution algorithm executed on each ofthe main traffic participant vehicle and the conflicted recipientvehicle to each make a same distributed decision whether to proceed withthe maneuver.
 2. The vehicle of claim 1, wherein the lane change intentmessage includes urgency information with respect to the main trafficparticipant vehicle, the response message indicating conflict with useof the road resource includes urgency information with respect to theconflicted recipient vehicle, and the conflict resolution algorithmaccounts for the urgency information to determine relative need of themain traffic participant vehicle and the conflicted recipient vehicle toperform the maneuver.
 3. The vehicle of claim 1, wherein the responsemessage includes parameters of intended movement of the one of therecipient vehicles, and the one or more controllers are furtherprogrammed to use, as inputs to make the distributed decision whether toproceed with the maneuver, the parameters of the maneuver to beperformed by the main traffic participant vehicle and the parameters ofthe intended movement of the one of the recipient vehicles.
 4. Thevehicle of claim 1, wherein the one or more controllers are furtherprogrammed to: responsive to receipt of the response message indicatingconflict with use of the road resource, send a conflict confirmationmessage including inputs to be used by the conflict resolutionalgorithm; responsive to the conflict resolution algorithm deciding infavor of the main traffic participant vehicle, receive, from theconflicted recipient vehicle a reservation message confirming that themain traffic participant vehicle is to utilize the road resourcerequired for performance of the maneuver; and responsive to the conflictresolution algorithm deciding in favor of the conflicted recipientvehicle, receive, from the conflicted recipient vehicle, a reservationmessage confirming that the main traffic participant vehicle is not toutilize the road resource required for performance of the maneuver. 5.The vehicle of claim 1, wherein the one or more controllers are furtherprogrammed to: responsive to receipt of the response message indicatingconflict with use of the road resource, send a conflict confirmationmessage to the conflicted recipient vehicle including a plurality ofpathways to use as options for performance of the maneuver; and receive,from the conflicted recipient vehicle, a reservation message indicatingwhich one of the plurality of pathways is to be used by the main trafficparticipant vehicle to perform the maneuver.
 6. The vehicle of claim 1,wherein the one or more controllers are further programmed to:responsive to receipt of the response message, the response messageindicating conflict with use of the road resource and including aplurality of pathways to use as options for performance of the maneuver,send a conflict confirmation message to the conflicted recipient vehicleindicating which one of the plurality of pathways is to be used by themain traffic participant vehicle to perform the maneuver; and receive,from the conflicted recipient vehicle, a reservation message confirmingwhich one of the plurality of pathways is to be used by the main trafficparticipant vehicle to perform the maneuver.
 7. The vehicle of claim 1,wherein the one or more controllers are further programmed to: include,in the lane change intent message, a list of identifiers of the one ormore recipient vehicles required to respond to approve the maneuver, theone or more recipient vehicles being determined according to vehiclelocation information received from the one or more recipient vehicles;and responsive to failing to receive response messages within apredefined timeout period from each of the one or more recipientvehicles in the list, abort performance of the maneuver.
 8. The vehicleof claim 1, wherein the one or more controllers are further programmedto broadcast, from the vehicle to one or more recipient vehicles, anurgent lane change intent message, the lane change intent messageindicating parameters of a maneuver to be performed by the vehicleoperating as a main traffic participant vehicle, the maneuver requiringuse of a road resource, the lane change intent message further includinga reservation of the road resource regardless of conflicts of therecipient vehicles.
 9. A vehicle for performing traffic maneuvers,comprising: one or more controllers programmed to receive, from a maintraffic participant vehicle as a recipient vehicle, a lane change intentmessage, the lane change intent message indicating parameters of amaneuver to be performed by the main traffic participant vehicle, themaneuver requiring use of a road resource; and responsive to the roadresource being required by the recipient vehicle, perform a conflictresolution procedure between the main traffic participant vehicle andthe conflicted recipient vehicle, the conflict resolution procedureusing a pre-agreed identical conflict resolution algorithm executed oneach of the main traffic participant vehicle and the conflictedrecipient vehicle to each make a same distributed decision whether toproceed with the maneuver.
 10. The vehicle of claim 9, wherein the lanechange intent message includes urgency information with respect to themain traffic participant vehicle, the conflicted recipient vehicleprovides urgency information with respect to the conflicted recipientvehicle, and the conflict resolution algorithm accounts for the urgencyinformation to determine relative need of the main traffic participantvehicle and the conflicted recipient vehicle to perform the maneuver.11. The vehicle of claim 9, wherein the one or more controllers arefurther programmed to: send a response message including parameters ofintended movement of the recipient vehicle; and use, as inputs to makethe distributed decision whether to proceed with the maneuver, theparameters of the maneuver to be performed by the main trafficparticipant vehicle and the parameters of intended movement of therecipient vehicles.
 12. The vehicle of claim 9, wherein the one or morecontrollers are further programmed to: receive a conflict confirmationmessage including inputs to be used by the conflict resolution algorithmresponsive to sending a response message indicating conflict with use ofthe road resource; responsive to the conflict resolution algorithmdeciding in favor of the main traffic participant vehicle, send, to themain traffic participant vehicle, a reservation message confirming thatthe main traffic participant vehicle is to utilize the road resourcerequired for performance of the maneuver; and responsive to the conflictresolution algorithm deciding in favor of the conflicted recipientvehicle, send, to the main traffic participant vehicle, a reservationmessage confirming that the main traffic participant vehicle is not toutilize the road resource required for performance of the maneuver. 13.The vehicle of claim 9, wherein the one or more controllers are furtherprogrammed to: responsive to sending, to the main traffic participantvehicle, a response message indicating conflict with use of the roadresource, receive a conflict confirmation message from the main trafficparticipant vehicle including a plurality of pathways to use as optionsfor performance of the maneuver; and send, to the main trafficparticipant vehicle, a reservation message indicating which one of theplurality of pathways is to be used by the main traffic participantvehicle to perform the maneuver.
 14. The vehicle of claim 9, wherein theone or more controllers are further programmed to: responsive tosending, to the main traffic participant vehicle, a response messageindicating conflict with use of the road resource and including aplurality of pathways to use as options for performance of the maneuver,receive a conflict confirmation message from the main trafficparticipant vehicle indicating which one of the plurality of pathways isto be used by the main traffic participant vehicle to perform themaneuver; and send, to the main traffic participant vehicle, areservation message indicating which one of the plurality of pathways isto be used by the main traffic participant vehicle to perform themaneuver.
 15. The vehicle of claim 9, wherein the one or morecontrollers are further programmed to: identify, in the lane changeintent message, a list of identifiers of the one or more recipientvehicles required to respond to approve the maneuver, the one or morerecipient vehicles being determined according to vehicle locationinformation received from the one or more recipient vehicles; andrespond to the lane change intent message with a response messageresponsive to the list of identifiers including an identifier of therecipient vehicle.
 16. The vehicle of claim 9, wherein the one or morecontrollers are further programmed to: receive a broadcast, from themain traffic participant vehicle, of an urgent lane change intentmessage, the lane change intent message indicating parameters of amaneuver to be performed by the main traffic participant vehicle, themaneuver requiring use of a road resource, the lane change intentmessage further including a reservation of the road resource regardlessof conflicts of the recipient vehicle; and maneuver to avoid use of theroad resource.
 17. A method for performing traffic maneuvers,comprising: broadcasting, from a vehicle to one or more recipientvehicles, a lane change intent message, the lane change intent messageindicating parameters of a maneuver to be performed by the vehicleoperating as a main traffic participant vehicle, the maneuver requiringuse of a road resource; receiving, from the one or more recipientvehicles, one or more respective response messages indicating approvalor disapproval of performance of the maneuver; responsive to theresponse messages all indicating approval of the maneuver, sending areservation message to at least the one or more recipient vehiclesindicating that the main traffic participant vehicle is to perform themaneuver utilizing the road resource; and responsive to one of therecipient vehicles returning a response message indicating conflict withuse of the road resource required for performance of the maneuver,performing a conflict resolution procedure between the main trafficparticipant vehicle and the conflicted recipient vehicle, the conflictresolution procedure using a pre-agreed identical conflict resolutionalgorithm executed on each of the main traffic participant vehicle andthe conflicted recipient vehicle to each make a same distributeddecision whether to proceed with the maneuver.
 18. The method of claim17, wherein the lane change intent message includes urgency informationwith respect to the main traffic participant vehicle, the responsemessage indicating conflict with use of the road resource includesurgency information with respect to the conflicted recipient vehicle,and the conflict resolution algorithm accounts for the urgencyinformation to determine relative need of the main traffic participantvehicle and the conflicted recipient vehicle to perform the maneuver.19. The method of claim 17, wherein the response message includesparameters of intended movement of the one of the recipient vehicles,further comprising using, as inputs to make the distributed decisionwhether to proceed with the maneuver, the parameters of the maneuver tobe performed by the main traffic participant vehicle and the parametersof intended movement of the one of the recipient vehicles.
 20. Themethod of claim 17, further comprising: responsive to receipt of theresponse message indicating conflict with use of the road resource,sending a conflict confirmation message including inputs to be used bythe conflict resolution algorithm; responsive to the conflict resolutionalgorithm deciding in favor of the main traffic participant vehicle,receiving, from the conflicted recipient vehicle a reservation messageconfirming that the main traffic participant vehicle is to utilize theroad resource required for performance of the maneuver; and responsiveto the conflict resolution algorithm deciding in favor of the conflictedrecipient vehicle, receiving, from the conflicted recipient vehicle, areservation message confirming that the main traffic participant vehicleis not to utilize the road resource required for performance of themaneuver.
 21. The method of claim 17, further comprising: responsive toreceipt of the response message indicating conflict with use of the roadresource, sending a conflict confirmation message to the conflictedrecipient vehicle including a plurality of pathways to use as optionsfor performance of the maneuver; and receiving, from the conflictedrecipient vehicle, a reservation message indicating which one of theplurality of pathways is to be used by the main traffic participantvehicle to perform the maneuver.
 22. The method of claim 17, furthercomprising: responsive to receiving the response message, the responsemessage indicating conflict with use of the road resource and includinga plurality of pathways to use as options for performance of themaneuver, send a conflict confirmation message to the conflictedrecipient vehicle indicating which one of the plurality of pathways isto be used by the main traffic participant vehicle to perform themaneuver; and receiving, from the conflicted recipient vehicle, areservation message confirming which one of the plurality of pathways isto be used by the main traffic participant vehicle to perform themaneuver.
 23. The method of claim 17, further comprising: including, inthe lane change intent message, a list of identifiers of the one or morerecipient vehicles required to respond to approve the maneuver, the oneor more recipient vehicles being determined according to vehiclelocation information received from the one or more recipient vehicles;and responsive to failing to receive response messages within apredefined timeout period from each of the one or more recipientvehicles in the list, aborting performance of the maneuver.
 24. Themethod of claim 17, further comprising broadcasting, from the vehicle toone or more recipient vehicles, an urgent lane change intent message,the lane change intent message indicating parameters of a maneuver to beperformed by the vehicle operating as a main traffic participantvehicle, the maneuver requiring use of a road resource, the lane changeintent message further including a reservation of the road resourceregardless of conflicts of the recipient vehicles.